Alexis Sanchez is Arsenal's top scorer in the PL this season after he scored five goals in two games against Leicester City and Manchester UnitedGetty

Arsenal star Alexis Sanchez is a major doubt for Chile's World Cup qualifier clash against Brazil on Friday (9 October) after the forward picked up a minor injury during the Gunners' 3-0 win over Manchester United on Sunday (4 October). The Chilean international has not taken part in a full training session since joining the squad early this week.

The former Barcelona attacker was substituted midway through the second-half during the north London club's win over the Red Devils, with Arsene Wenger confirming that it was a minor groin injury. The French manager, however, admitted that he was powerless to stop him from joining up with his national team for their crucial clash against the Selecao.

"He has a little groin problem. Unfortunately he goes to Chile. You cannot stop him from going to Chile and he loves so much to play for his country and he will play against Brazil [on Friday] and Peru [next] Tuesday so the game at home against Brazil he will not want to miss. Hopefully he will come back in good shape," Wenger said.

The north London club's medical staff are reportedly in regular contract with their Chilean counterparts to make sure no unnecessary risks are taken with Sanchez, who has just struck form following a slow start to the season owing to Chile's participation and eventual victory in the 2014 Copa America. He has scored six goals in the last three games for Arsenal, including a brace against Manchester United. Jorge Sampaoli, however, is not confident about his participation against Brazil along with teammate Arturo Vidal, who is also struggling with a knee injury.

Wenger will be hoping that the injury is indeed a minor one, as Arsenal have a crucial week ahead of them following the international break. Apart from the Premier League commitments, they have a crucial double header against Bayern Munich in the Champions League, and it is a must win game for the Gunners after they lost their opening two group games to Dinamo Zagreb and Olympiacos, leaving their hopes of qualifying for the knockout phase hanging by a thread.